Molecular typing of enteroviruses: comparing 5'UTR, VP1 and whole genome sequencing methods.

Enteroviruses (EV) commonly cause hand, foot and mouth disease (HFMD), and can also cause potentially fatal neurological and systemic complications. In our laboratory, sequencing 5' untranslated region (UTR) of the viral genome has been the routine method of genotyping EVs. During a recent localised outbreak of aseptic meningitis, sequencing the 5'UTR identified the causative virus as EV-A71, which did not fit with the clinical syndrome or illness severity. When genotyped using a different target gene, VP1, the result was different. This led us to evaluate the accuracy of the two different target genome regions and compare them against whole genome sequencing (WGS). We aimed to optimise the algorithm for detection and characterisation of EVs in the diagnostic laboratory. We hypothesised that VP1 and WGS genotyping would provide different results than 5'UTR in a subset of samples. Clinical samples from around New South Wales which were positive for EV by commercial polymerase chain reaction (PCR) assays were genotyped by targeting three different viral genome regions: the 5'UTR, VP1 and WGS. Sequencing was performed by Sanger and next generation sequencing. The subtyping results were compared. Of the 74/118 (63%) samples that were successfully typed using both the 5'UTR and the VP1 method, the EV typing result was identical for 46/74 (62%) samples compared to WGS as the gold standard. The same EV group but different EV types were found in 22/74 (30%) samples, and 6/74 (8%) samples belonged to different EV groups depending on typing method used. Genotyping with WGS and VP1 is more accurate than 5'UTR. Genotyping by the 5'UTR method is very sensitive, but less specific.

Survival after pulmonary edema due to enterovirus 71 encephalitis.

BACKGROUND: A distinctive pattern of enterovirus 71 (EV71) infection, characterized by fever, exanthem, acute pulmonary edema (PE), brainstem encephalitis, and flaccid paresis, affects infants and young children. Most die rapidly owing to respiratory failure and fulminant PE. METHOD: The authors report short- and long-term outcome of six survivors of the acute illness. RESULTS: In the context of acute PE and widespread weakness, recognition of the underlying neurologic disorder was facilitated by the distinctive pattern of MRI signal abnormalities in posterior pons and medulla. EV71-specific PCR of clinical samples helped confirm the diagnosis. Acute PE was managed with mechanical ventilation, afterload reduction, and inotrope support, and resolved completely over days. One patient with minimal neurologic recovery died 9 weeks after disease onset. The other patients have residual neurologic dysfunction, varying from subtle monoparesis to severe bulbar dysfunction, central and peripheral respiratory failure, and flaccid quadriparesis. Faster neurologic recovery was associated with less long-term deficit. Long-term outcome was similar in patients treated with and without pleconaril or IV immunoglobulin. Three long-term survivors treated with IV corticosteroids had less severe long-term neurologic disability than two not treated with steroids. CONCLUSION: Acute pulmonary edema and encephalomyelitis occurs with EV71 infection in infants. Long-term neurologic outcome varied from minor, focal weakness to profound, global motor dysfunction with respiratory failure.

22q11 deletion and polymicrogyria--cause or coincidence?

We report a familial case of velocardiofacial syndrome (VCFS) with polymicrogyria to provide further support for the association of disorders of cortical development with del(22q11) syndromes.

Autoimmunity to munc-18 in Rasmussen's encephalitis.

Rasmussen's encephalitis (RE) is a rare disease of the central nervous system characterized by severe epileptic seizures, progressive degeneration of a single cerebral hemisphere, and autoimmunity directed against glutamate receptor subunit, GluR3. We report here the identification of high-titer autoantibodies directed against munc-18 in the serum of a single patient with RE previously shown to have anti-GluR3 antibodies. Munc-18 is an intracellular protein residing in presynaptic terminals, which is required for secretion of neurotransmitters. These findings are consistent with the possibility of intermolecular epitope spreading between GluR3, a postsynaptic cell surface protein, and munc-18, a presynaptic intracellular protein. Immune attack on these two proteins, which participate at distinct steps of synaptic transmission, could act in an additive or synergistic manner to impair synaptic function and lead to seizures and neuronal death.

Immunoglobulin G and complement immunoreactivity in the cerebral cortex of patients with Rasmussen's encephalitis.

OBJECTIVE: To provide evidence that complement (C')-dependent processes may be involved in Rasmussen's encephalitis (RE). BACKGROUND: RE is a rare, progressive, childhood epilepsy syndrome associated with inflammation and neuronal cell loss in a single cerebral hemisphere. Recent work suggests an autoimmune immunoglobulin (Ig) G-mediated process is important in disease pathogenesis. METHODS: Brain samples from RE and complex partial epilepsy control patients were analyzed immunohistochemically. Sections were stained for IgG and the C' factors C4, C8, and the membrane attack complex (MAC). RESULTS: Brain samples from three of five patients with active, progressive RE but neither of two chronic RE nor five control epilepsy patients demonstrated immunoreactivity for IgG, C4, C8, and MAC on discrete patches of cerebrocortical neurons. Intensely activated glial fibrillary acid protein-positive astrocytes were found in areas overlapping these patches. CONCLUSION: Focally distributed IgG- and C'-positive neurons were found to colocalize with activated astrocytes, suggesting focal IgG-dependent classical C' cascade pathway activation with attendant tissue damage in this subset of RE patients. Intraparenchymal C' activation triggered by pathogenic antibodies may contribute to the development of focal inflammation, neuronal cell loss, and pharmacoresistant seizures in some patients with this disease. This process may be an important component in the initial, active phase of RE.

Clinical and electroencephalographic correlates in Rasmussen's encephalitis.

PURPOSE: Rasmussen's encephalitis (RE) is a progressive childhood disease characterized by unilateral brain dysfunction, seizures, and inflammatory histopathology. Converging lines of evidence suggest that an autoimmune process is important in the pathogenesis of RE. METHODS: Two patients with pathologically confirmed RE and increased levels of circulating glutamate receptor subunit (GluR3) antibodies were studied prospectively before, during, and after trials of plasmapheresis (PEX) and other immunomodulation. Frequency, duration, and intensity of clinical seizures were directly correlated with the abundance of interictal epileptiform activity on serial EEGs. RESULTS: Serial EEGs in these patients suggest that early in the course of RE interictal epileptiform activity is localized to the affected hemisphere and that disease progression is associated with increasingly frequent bilaterally synchronous and contralateral epileptiform activity. CONCLUSIONS: The clinical and EEG parameters of epileptogenesis were transiently diminished by PEX, which suggests that circulating factors induce dose-dependent, reversible epileptogenic effects in some patients with RE.

Rasmussen's encephalitis: an autoimmune disorder?

Rasmussen's encephalitis is a rare progressive pediatric epileptic syndrome. Recent evidence from experimental animals and patients with the disease suggests an important role for both humoral and cell-mediated immune mechanisms in the pathogenesis of this disease. The glutamate receptor subunit GluR3 may be an important autoantigen in the disease. (This review has been modified from a review published in Current Opinion in Neurology 1996, 9:141-145.)

Rasmussen's encephalitis: an autoimmune disorder?

Rasmussen's encephalitis is a rare progressive pediatric epileptic syndrome. Recent evidence from experimental animals and patients with the disease suggests an important role for both humoral- and cell-mediated immune mechanisms in the pathogenesis of this disease. The glutamate receptor subunit, GluR3, may be an important autoantigen in the disease.

Plasmapheresis in Rasmussen's encephalitis.

Rasmussen's encephalitis (RE) is a progressive childhood disorder characterized by intractable focal seizures, hemiplegia, dementia, and inflammatory histopathology. The process is typically limited to one cerebral hemisphere. We report four patients with pathologically confirmed RE who were treated with repeated plasmapheresis. Three patients exhibited repeated, dramatic, transient responses to plasmapheresis, manifested by reduced seizure frequency and improved neurologic function. One patient exhibited marginal improvement after treatment with plasmapheresis. These observations indicate that circulating factors, likely autoantibodies, are pathogenic in at least some patients with RE and suggest that RE is an autoimmune disease. Plasmapheresis may be a useful adjunctive therapy in status epilepticus, and can also aid in assessment of residual function in the diseased hemisphere before surgical resection.

Autoantibodies to glutamate receptor GluR3 in Rasmussen's encephalitis.

Rasmussen's encephalitis is a progressive childhood disease of unknown cause characterized by severe epilepsy, hemiplegia, dementia, and inflammation of the brain. During efforts to raise antibodies to recombinant glutamate receptors (GluRs), behaviors typical of seizures and histopathologic features mimicking Rasmussen's encephalitis were found in two rabbits immunized with GluR3 protein. A correlation was found between the presence of Rasmussen's encephalitis and serum antibodies to GluR3 detected by protein immunoblot analysis and by immunoreactivity to transfected cells expressing GluR3. Repeated plasma exchanges in one seriously ill child transiently reduced serum titers of GluR3 antibodies, decreased seizure frequency, and improved neurologic function. Thus, GluR3 is an autoantigen in Rasmussen's encephalitis, and an autoimmune process may underlie this disease.

Race, sex, and puberty influence onset, severity, and outcome in juvenile myasthenia gravis.

We assessed the influence of race, sex, and puberty upon clinical features and outcome in 115 patients with autoimmune juvenile myasthenia gravis (JMG). These demographic variables influenced not only disease incidence but also disease severity, response to therapy, and outcome, despite comparable therapeutic strategies. Among white patients, those with prepubertal onset had low incidence and equal sex ratio; the incidence in females increased during and after puberty; males had lesser disease severity than females during and after puberty (p < 0.05); spontaneous remissions were most frequent (44%, p = 0.001) and persistence of active JMG for more than 10 years was least frequent (p = 0.05) in patients with prepubertal onset; remissions were more frequent after early than late thymectomy (p = 0.03); and final disease severity was less after early than late thymectomy. Black patients had similar incidence, disease severity, and sex ratio (F:M = 2:1) with pre-, peri-, or postpubertal disease onset; infrequent spontaneous or treatment-induced remissions; and the same final disease severity after early or late thymectomy. These observations imply that race and sex hormones modify the clinical features and outcome of JMG; spontaneous remissions are common in white patients with prepubertal disease onset; early thymectomy may be more beneficial than late thymectomy in white patients; and the role of thymectomy in the youngest patients is uncertain. We suggest that demographic factors should be considered when evaluating past and future therapeutic strategies for JMG.

Acetylcholine receptor antibodies in juvenile myasthenia gravis.

We analyzed relationships among pubertal stage at disease onset, sex, disease severity, and acetylcholine receptor antibody (AChR Ab) levels in 46 patients with autoimmune juvenile myasthenia gravis (JMG). Female predominance was least in children with prepubertal disease onset (F:M = 1.3:1) and increased in patients with peripubertal (F:M = 1.8:1) and postpubertal (F:M = 14:1) onset. Seronegative JMG was most common in children with early disease onset: 4 of 9 (44%) with prepubertal, 4 of 22 (18%) with peripubertal, and 0 of 15 (0%) with postpubertal onset were seronegative. The rapid therapeutic response to plasmapheresis was useful in distinguishing some patients with seronegative JMG from those with congenital myasthenia gravis (CMG). The high frequency of seronegative JMG in patients with prepubertal onset indicates that AChR Ab assays do not adequately discriminate between JMG and CMG in young children. Furthermore, the different sex distribution in patients with different pubertal stages at disease onset suggests that sex hormones play an important modulating role in JMG.

Mesenrhombencephalitis: MR findings in nine patients.

OBJECTIVE: Mesenrhombencephalitis is a serious form of brainstem inflammation predominantly involving the deep and vital portions of the brain, that is, the mesencephalon (midbrain) and rhombencephalon (pons, medulla). Mesenrhombencephalitis is difficult to diagnose on the basis of clinical and laboratory findings alone, and access to this portion of the brain for surgical biopsy carries high morbidity. We describe the MR appearance of mesenrhombencephalitis and correlate the imaging findings with clinical information. MATERIALS AND METHODS: Unenhanced and contrast-enhanced MR images of nine patients with mesenrhombencephalitis were reviewed retrospectively and correlated with clinical, laboratory, and pathologic data. The patients were categorized according to the cause of the disease: three had herpes simplex, one had Listeria monocytogenes, and five had mesenrhombencephalitis of undetermined cause. The three patients with clinical and MR evidence of herpes simplex mesenrhombencephalitis (one confirmed by brain biopsy) were comatose at presentation, with cranial nerve abnormalities in two and seizures in one. One patient with L. monocytogenes (established by blood culture) had cranial nerve palsies, fever, and pain in the ear. Five additional patients had headache (three), fever (three), nausea and vomiting (four), cranial nerve palsies (three), coma (two), and hyporeflexia (one) or hyperreflexia (four). Brain biopsy performed in two patients revealed chronic inflammation of unspecified cause; in one, it was compatible with viral encephalitis. RESULTS: MR images in three patients with herpes simplex mesenrhombencephalitis showed T2 signal hyperintensity in the midbrain (two), pons (one), medulla (one), and temporal lobes (three). Parenchymal foci of hemorrhage (methemoglobin, one patient) and leptomeningeal enhancement (one patient) were identified in the temporal lobes. T2-weighted MR images in one patient with L. monocytogenes showed signal hyperintensity in the brainstem, vermis, midbrain, and internal capsules. On T1-weighted images, low signal was present in these areas, which enhanced with paramagnetic contrast agents. In the remaining five patients, T2-weighted MR images showed patchy signal hyperintensity in the pons, medulla, and thalamus in three each and in the midbrain and temporal lobes in one each. T1-weighted MR images showed normal findings (two) or signal hypointensity in the thalamus and pons in one patient each. Areas of leptomeningeal and parenchymal enhancement were identified in one patient each. Brainstem swelling was seen in three patients, one of whom had petechial hemorrhage in the pons and hydrocephalus. CONCLUSION: Mesenrhombencephalitis is a serious illness that is diagnosed by a combination of imaging, clinical, laboratory, and pathologic studies. MR imaging may be crucial to the early diagnosis of this illness, and radiologists must be familiar with this uncommon entity and its MR findings in order to make timely diagnoses and facilitate treatment.

An infant with macrocephaly, abnormal neuronal migration and persistent olfactory ventricles.

An asphyxiated male infant was delivered by cesarean section at 38 weeks gestation. The patient was macrocephalic with clinical evidence of fetal immobility syndrome. He died aged two days. Autopsy revealed excessive brain weight, pachygyria, enlarged olfactory tracts and hypoplastic optic nerves. Microscopy revealed evidence of impaired neuronal migration throughout the cortex. The olfactory bulbs showed persistence of the primitive olfactory ventricles and absence of olfactory glomeruli. There was persistence of the fetal connection between lateral and olfactory ventricles. The lateral geniculate nuclei, inferior olivary nuclei and dentate nuclei of the cerebellum were abnormally formed. Relevant aspects of fetal brain development and clinical neuropathologic syndromes are discussed.

Relative disease severity in siblings with myotonic dystrophy.

Myotonic dystrophy is an autosomal dominant disorder in which an early-onset form is characteristically inherited from the mother. We studied 17 affected sibling pairs from 15 families in which two or more affected children were born to mothers with myotonic dystrophy. Later-born affected children suffered more severe disease than their first-born siblings in 13 of 17 sibling pairs. Later-born affected siblings displayed significantly more neonatal feeding difficulties, later age when first sitting alone, later age when first walking alone, and a higher incidence of scoliosis. The overall difference in disease severity between affected siblings increased as the age difference between them increased, suggesting that increasing maternal age is a factor in the relative disease severity of affected children. These findings may have relevance for genetic counseling.

Renal consequences of immobilisation in children with fractured femurs.

Parameters of renal function and calcium homeostasis were studied in 8 children, immobilised for 5-9 weeks with fractured femurs, weekly during immobilisation and fourth weekly following mobilisation until all parameters returned to normal. During immobilisation 1 patient became hypercalcaemic, but all showed an increase in serum calcium and all developed hypercalciuria. During immobilisation all showed diminished urine osomolality after a 12-hour fast (mean 591 +/- 133 mOsm/kg) which improved 4-39 weeks after mobilisation (mean 973 +/- 87 mOsm/kg). Serum creatinine, urinary beta-2-microglobulin and renal ultrasound appearances were all normal. An inverse relationship, R = -0.70, was demonstrated between serum calcium and fasting urine osmolality during immobilisation. Three patients showed diminished urinary concentrating ability beyond 4 weeks after mobilisation. For 1 patient this defect persisted for 8 months and glomerular filtration rate was diminished 9 months after mobilisation, raising the possibility of long term renal damage in immobilised patients.